The back contains 6 scales of the following types:
| Type (click to view scale details) |
Range & Units | Numbered | Geometry | Location |
|---|---|---|---|---|
| Degree | 0 - 90, Degrees | Every 5 degrees | Circular, concentric | The entire outer circle on the back of an astrolabe. |
| Zodiacal signs | 0 - 30, Zodiacal divisions, equal or unequal | Every 5 | Circular, concentric | Circular scale immediately inside the outer scale - refers to the full circle |
| Calendar | First day of month - Last day of month, Days of year | Every 10 and end of month days | Circular, eccentric | Circular scale second in from the outer scale - refers to the full circle. |
| Lunar Mansions | Lunar mansion | Not numbered | Circular, concentric | Circular scale third in from the outer scale - refers to the full circle. |
| Unequal hours | 1 - 6, 1/12 of daylight | Not numbered hours | Arc | The upper two quadrants of the back of the instrument |
| Shadow square | 1 - 16, Fingers | Not numbered fingers | Box | The lower two quadrants of the back of the instrument |